JP7782178B2 - Work vehicles - Google Patents

Description

The present invention relates to work vehicles such as tractors, chemical spraying vehicles, and rice transplanters.

Regarding autonomous vehicles, the technology described in Patent Document 1 below is known.
Patent Document 1 (JP 2012-11969 A) discloses a technology for a cruise system that automatically applies a braking force to stop a vehicle when a preceding vehicle stops, and for a vehicle equipped with an idle stop system that automatically stops the engine, that activates a parking brake using an electric motor when the engine is stopped by the idle stop system.

JP 2012-11969 A

(Problems with the prior art)
The technology disclosed in Patent Document 1 relates to vehicles such as automobiles and trucks that travel on paved roads. However, in agricultural work vehicles such as tractors that travel on fields such as farms and rice paddies, the vehicle is typically braked by hydraulic brakes activated by engine power during autonomous driving. Therefore, in a work vehicle such as a tractor, if the engine stops, the hydraulic brakes stop working, and if the engine is stopped during an emergency stop or idling stop, the brakes stop working. Therefore, if the brakes are not quickly applied following the engine stop, there is a risk that the vehicle will not be able to stop on a slope, etc. Furthermore, since agricultural work vehicles such as tractors travel on rough roads, the driving torque is large. Therefore, if the brakes are applied while the engine is running, the brakes will drag, accelerating wear of the brake mechanism.

The technical objective of this invention is to ensure that a vehicle can be stopped at the appropriate timing when it is being driven automatically.

In order to solve the technical problem, the invention described in claim 1 is a work vehicle comprising: a traveling vehicle body; a driver's seat in which a driver can ride; a braking device that brakes the traveling vehicle body; an electric cylinder supported on a floor on which the driver's seat is installed and that activates the braking device; and a control unit that causes the traveling vehicle body to automatically travel along a predetermined travel route, the control unit pre-stores the operating position of the electric cylinder at which the braking device is activated, and if the engine speed does not reach a predetermined value during automatic travel, the control unit moves the electric cylinder to the operating position to brake the traveling vehicle body using the braking device, and when the electric cylinder moves to the operating position, the control unit stops the electric cylinder at the operating position for a predetermined time, and after the predetermined time has elapsed, the control unit moves the electric cylinder to a release position where the braking device is not activated, and when the power to the work vehicle is turned on, the control unit moves the electric cylinder between the operating position and the release position, and if the electric cylinder does not reach at least one of the operating position and the release position, the control unit restricts the start of the automatic travel.

According to the invention described in claim 1, by activating the braking device with the transmission cylinder when the engine speed does not reach a predetermined value during automatic driving, it is possible to reliably maintain the vehicle stopped at the appropriate timing when the vehicle is being driven automatically.
Furthermore, according to the invention described in claim 1, after a predetermined time has elapsed since the electric cylinder was moved to the operating position, it is moved to the release position, thereby preventing the electric cylinder from interfering with the operator's manual release of the braking device.
Furthermore, according to the invention described in claim 1, if the electric cylinder does not reach the operating position or the released position when the work vehicle is powered on, automatic driving cannot be started, thereby improving the safety of automatic driving.

FIG. 1 is an explanatory diagram of a control system for a work vehicle according to this embodiment. FIG. 2 is an explanatory view of the main parts inside the tractor according to the embodiment. FIG. 3 is an explanatory diagram including a braking link mechanism according to the embodiment. FIG. 4 is an enlarged view of a main part of the parking lever according to the embodiment. FIG. 5 is a functional block diagram of the control system for the work vehicle according to this embodiment.

Next, examples that are specific examples of the embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples.
In the description of the embodiment, the left and right directions in the forward direction of the vehicle will be referred to as left and right, respectively, and the forward direction will be referred to as front, and the backward direction will be referred to as rear.
In the following description using the drawings, illustrations of components other than those necessary for the description are omitted as appropriate to facilitate understanding.

Preferred embodiments of the present invention will now be described with reference to the drawings.
FIG. 1 is an explanatory diagram of a control system for a work vehicle according to this embodiment.
1, the work vehicle control system S of this embodiment has a tractor 1, an agricultural machine, as an example of a work vehicle. The tractor 1 has a work implement 2 at its rear. As the work implement 2, a conventionally known work implement such as a tiller, plow, fertilizer applicator, or seed sowing machine can be used depending on the work to be performed in the field. Furthermore, while a tractor 1 is shown as an example of a work vehicle, the present invention is not limited to this and can be applied to any work vehicle such as a chemical sprayer, rice transplanter, combine harvester, or seedling transplanter.

1, the work vehicle control system S of the embodiment has a server 101 as an example of an information processing device. The server 101 is configured to be able to send and receive information to and from a tractor 1 via an internetwork N as an example of a communication line. The tractor 1 of the embodiment is configured to be able to communicate with the server 101 via the network N by wireless communication.
Furthermore, the work vehicle control system S of the embodiment includes a tablet terminal TAB, which is an example of a terminal used by a worker and is an example of an instruction device. The tablet terminal TAB is configured to be able to send and receive information to and from the tractor 1 via wireless communication.

(Tractor description)
The tractor 1 has front wheels 12, 12 and rear wheels 13, 13 on a traveling body 11. An engine 16 is mounted inside a hood 14 at the front of the traveling body 11. Power from the engine 16 is transmitted to the front wheels 12 and rear wheels 13 via a speed change transmission unit in a transmission case 15. Power from the engine 16 is also transmitted to the work implement 2 via a PTO (Power Take Off) shaft (not shown).

FIG. 2 is an explanatory view of the main parts inside the tractor according to the embodiment.
FIG. 3 is an explanatory diagram including a braking link mechanism according to the embodiment.
FIG. 4 is an enlarged view of a main part of the parking lever according to the embodiment.
2 to 4, a driver's seat (seat) 18 in which an operator can sit is disposed inside a cabin 17 of the tractor 1. A parking lever 21, which is an example of a braking member, is disposed to the side of the driver's seat 18. A grip 21a, which is an example of a gripping portion for the operator to grasp, is provided at the front end of the parking lever 21. The parking lever 21 is supported rotatably around a rotation shaft 21b at the rear end.

In Figure 4, a parking lever sensor 20, an example of a first detection member, is located near the parking lever 21. The parking lever sensor 20 detects the position of the parking lever 21, i.e., whether the grip 21a is raised upward (brake applied position) or lowered downward (brake released position).

One end (upper end) 22a of a first link member 22 is connected to the lower portion 21c of the parking lever 21. One end (front end) 23a of a second link member 23 is rotatably connected to the other end (lower end) 22b of the first link member 22. The other end (rear end) 23b of the second link member 23 is rotatably supported on the vehicle body 11. One end (upper end) 24a of a third link member 24 is rotatably connected to the second link member 23 at a position closer to the front end 23a than the rear end 23b. One end (rear end) 26a of a fourth link member 26 is connected to the other end (lower end) 24b of the third link member 24. The other end (front end) 26b of the fourth link member 26 is connected to a brake shaft 27a of a rear wheel brake 27, which serves as an example of a braking device.

Therefore, when an operator grasps the grip 21a of the parking lever 21 and moves it upward, rotation is transmitted to the brake shaft 27a via each link member 22 to 26, the rear wheel brake 27 is activated, and the rear wheel 13 is braked (the brake is applied).
The link members 22 to 26 constitute the link mechanisms 22 to 26 of the embodiment that transmit the behavior of the parking lever 21 to the rear wheel brake 27 .

An electric cylinder 31, an example of an electric actuating member, is disposed diagonally rearward of the parking lever 21. In this embodiment, the parking lever 21 and electric cylinder 31 are disposed above (at a higher position than) the floor 19 of the cabin 17. Therefore, compared to when the parking lever 21 and other components are disposed lower than the floor 19, splashed mud, pebbles, sand, etc. are less likely to come into contact with the parking lever 21 and other components, thereby reducing malfunctions of the parking lever 21 and other components.

The electric cylinder 31 has a cylinder body 31a supported by the traveling vehicle body 11. The cylinder body 31a is provided with a plunger 31b that is extendable in the front-rear direction relative to the cylinder body 31a. A long hole 31c extending in the extension/contraction direction is formed at the front end of the plunger 31b. One end 22a of the first link member 22 is rotatably connected to the long hole 31c and movably along the long hole 31c. The electric cylinder 31 in this embodiment is powered by a battery (not shown) and is an electrically operated member that can be operated in response to an electric signal.
A cylinder sensor 32, which serves as an example of a second detection means for detecting the position of the plunger 31b, is disposed in the electric cylinder 31. The cylinder sensor 32 detects whether the plunger 31b is in an extended position (an actuated position of the rear wheel brake 27) or in a retracted position (a released position of the rear wheel brake 27).

In addition, in the embodiment, when the plunger 31b is moved to the release position, if an operator attempts to manually move the parking lever 21 to the brake application position, one end 22a of the first link member 22 can move forward along the long hole 31c, and the parking lever 21 can be moved to the brake application position without being obstructed by the electric cylinder 31.
When the plunger 31b moves to the operating position, the rear edge of the elongated hole 31c presses the end 22a of the first link member 22, moving the parking lever 21 to the brake operating position. When the plunger 31b moves from the operating position to the release position, the end 22a simply moves along the elongated hole 31c, and the parking lever 21 is maintained in the brake operating position.

(Explanation of functional block diagram)
FIG. 5 is a functional block diagram of the control system for the work vehicle according to this embodiment.
5, the work vehicle control system S of this embodiment includes a control unit CA of the tractor 1, a control unit CB of the tablet terminal TAB, and a control unit (not shown) of the server 101. Each control unit CA, CB is made up of an input/output interface (I/O) for inputting and outputting signals to and from the outside, a ROM (read-only memory) in which programs and information for performing necessary processing are stored, a RAM (random access memory) for temporarily storing necessary data, a CPU (central processing unit) for performing processing according to the programs stored in the ROM or the like, and a small information processing device having an oscillator or the like, a so-called microcomputer (an example of a computer device), and can realize various functions by executing programs stored in storage members such as the ROM, RAM, and non-volatile memory.

(Control unit of tablet device)
5, a control unit CB of the tablet terminal TAB receives output signals from signal output elements such as a touch panel TAB1 as an example of an input unit, input buttons TAB2 such as a power button and a volume change button, and a communication module TAB3 as an example of a communication unit. Therefore, information and signals can be input to the control unit CB of the tablet terminal TAB from the control unit CA of the tractor 1 and the server 101 via the communication module TAB3.

The control unit CB of the tablet terminal TAB is connected to a touch panel TAB1 (an example of a display), a speaker (not shown), a communication module TAB3, and other control elements (not shown), and outputs control signals to each control element. Therefore, information and signals can be output to the control unit CA of the tractor 1 and the server 101 via the communication module TAB3.

The control unit CB of the tablet terminal TAB has the function of executing processing in response to input signals from the touch panel TAB1 and outputting control signals to the respective control elements. In this embodiment, the control unit CB of the tablet terminal TAB has an operating system OS as an example of basic software, processing software AP1 as an example of application software and an example of processing means, and other application software (such as an internet browser or word processing software) not shown. The processing software AP1 has the following control means:

The information display means CB1 displays on the touch panel TAB1 an image for setting a work route, which is an automatic driving route, and information such as the set work route and the operating status of the tractor 1.
The work route generating means CB2 generates a work route in accordance with the user's work area settings.
The work start instruction means (autonomous driving start instruction means) CB3 transmits instruction information to start work, i.e., start autonomous driving, to the tractor 1 in response to an input by the operator to the touch panel TAB1.

(Control unit of tractor 1)
5, output signals from signal output elements such as a communication module 111 as an example of a communication unit, a GPS device 112 as an example of a positioning device, a gyro sensor 113 as an example of a direction acquisition device, and various other sensors (not shown) are input to the control unit CA of the tractor 1. Therefore, information and signals can be input to the control unit CA of the tractor 1 from the control unit CB of the tablet terminal TAB and the server 101 via the communication module 111.

The control unit CA of the tractor 1 is connected to the driving system, such as the engine and clutch, the steering system, such as the steering wheel, the communication module 111, and other control elements (not shown), and outputs control signals to each control element.

The control unit CA of the tractor 1 has a function of executing processing according to input signals from each signal output element and outputting a control signal to each of the control elements. The control unit CA of the tractor 1 in this embodiment has the following control means.
The positioning means CA1 acquires position information of the current position of the tractor 1 based on a signal from the GPS device 112.

The direction acquisition means CA2 acquires the traveling direction (forward direction) of the tractor 1 based on a signal from the gyro sensor 113. Note that the method for measuring direction is not limited to a gyro sensor, and any method capable of measuring direction, such as a compass, can be used.
The work path information acquisition unit CA3 acquires information about the work path. The work path information acquisition unit CA3 of the embodiment acquires and stores information including field position information, work area information, work path information, work start position information, and turning position information via communication with the tablet terminal TAB.

The travel control means CA4 controls the rotation speed of the engine 16, the rear wheel brake 27, the steering wheel (not shown), etc., to control the automatic travel of the tractor 1 (forward, backward, stopping, steering, turning).
The parking lever position detection means CA5 detects the position of the parking lever 21 based on the detection result of the parking lever sensor 20. That is, it detects whether the parking lever 21 is in the brake applied position, the brake released position, or somewhere between them. In the embodiment, the parking lever position detection means CA5 presets and stores the detection values of the parking lever sensor 20 at the brake applied position and the brake released position as initial values at the time of shipping from the factory, and detects the position of the parking lever 21 by comparing them with the initial values.

The electric cylinder position detection means CA6 detects the position of the plunger 31b of the electric cylinder 31 based on the detection results of the cylinder sensor 32. Therefore, it detects whether the electric cylinder 31 is in the activated position, the released position, or somewhere between them. Like the parking lever position detection means CA5, the electric cylinder position detection means CA6 also detects the position of the electric cylinder 31 by comparing it with a pre-stored initial value.

The electric cylinder defect determination means CA7 determines whether the electric cylinder 31 is defective. In this embodiment, the electric cylinder defect determination means CA7 moves the electric cylinder 31 between the activated and released positions when the tractor 1 is started (powered on) and determines whether it has not reached at least one of the activated and released positions. For example, if the electric cylinder 31 continues to move toward the activated (or released) position for five seconds or more but does not reach the activated (or released) position, it determines that the electric cylinder 31 has not reached the activated (or released) position. That is, if the electric cylinder 31 is not detected moving toward the activated (or released) position (if the rear wheel brake 27 never engages) or if the electric cylinder 31 is not detected moving toward the released position (if the rear wheel brake 27 never releases), it determines that the electric cylinder 31 is defective due to a malfunction of the electric cylinder 31 or something being caught in the plunger 31b. It is also determined to be defective if the detection value of the cylinder sensor 32 is clearly abnormal (a value exceeding the upper or lower limit). In this embodiment, if the electric cylinder defect determination means CA7 determines that the electric cylinder 31 is defective, it sends a control signal to the driving control means CA4 to restrict the automatic driving of the tractor 1 (preventing automatic driving and preventing the automatic driving mode from being started).

The engine speed determination means CA8 determines whether the speed of the engine 16 has not reached a predetermined speed. In the embodiment, as an example, it determines whether the engine speed has fallen from 500 revolutions per minute or more to less than 500 revolutions per minute.
The means CA9 for determining whether a set time has elapsed determines whether or not a time has elapsed from the activation to the deactivation of the electric cylinder 31. In the embodiment, as an example, the set time is preset to 2 seconds, and the electric cylinder 31 is released when 2 seconds have elapsed since the electric cylinder 31 was activated.

The electric cylinder control means CA10 controls the electric cylinder 31 to brake the traveling vehicle body 11 with the rear wheel brake 27. In this embodiment, the electric cylinder control means CA10 moves the electric cylinder 31 to the operating position when the engine speed falls below 500 revolutions per minute during automatic traveling. Furthermore, after the electric cylinder 31 moves to the operating position, the electric cylinder 31 is moved to the release position after the set time (2 seconds) has elapsed. In this embodiment, when the electric cylinder 31 is moved to the release position, it is held in the release position for the set time (2 seconds) before stopping the electric cylinder 31.

(Operation of the embodiment)
In the work vehicle control system S of the embodiment having the above configuration, if the engine 16 stops during automatic driving and the engine speed does not reach a predetermined value, for example, the electric cylinder 31 operates to apply the rear wheel brake 27. Therefore, if the engine 16 stops during automatic driving, the rear wheel brake 27 is automatically applied, and the tractor 1 is reliably held in a stopped state.
In particular, in the embodiment, an electric cylinder 31 is used, and no hydraulic cylinder is used. Therefore, the electric cylinder 31 can be operated even when the engine 16 is stopped. Therefore, compared to when a hydraulic cylinder is used, the rear wheel brake 27 can be reliably operated even when the engine 16 is stopped, improving safety. Note that, although the embodiment illustrates a case in which the engine speed is directly used, this is not limiting. For example, it is also possible to use whether the oil pressure (pressure in the hydraulic system), which fluctuates in conjunction with the engine speed, reaches a predetermined threshold.

Furthermore, in the tractor 1 of the embodiment, the electric cylinder 31 moves to the activated position, and then when a predetermined time (2 seconds) has elapsed, the electric cylinder 31 moves to the released position. In a configuration in which the electric cylinder 31 is not released, when the operator tries to move the parking lever 21 to the brake released position when resuming automatic traveling of the tractor 1, the electric cylinder 31 remains in the activated position, and the rear wheel brake 27 cannot be manually released.
In contrast, in this embodiment, the electric cylinder 31 moves to the release position after a predetermined time has elapsed. At this time, the parking lever 21 is held in the brake application position as described above. Therefore, with the electric cylinder 31 in the release position, when the automatic traveling of the tractor 1 is resumed, the operator can operate the parking lever 21 to move it to the brake release position, preventing the electric cylinder 31 from interfering with the operator's operation.

Furthermore, in the tractor 1 of this embodiment, a malfunction of the electric cylinder 31 is detected when the tractor 1 is started, and if a malfunction is detected, automatic driving becomes impossible. Therefore, compared to a configuration in which automatic driving is possible even when the electric cylinder 31 is not required, the tractor 1 does not stop even if the engine stops during automatic driving, reducing the risk of an accident, thereby improving safety.

1...Work vehicle,
11...Traveling vehicle body,
18...Driver's seat,
19...floor,
27...braking device,
31...electric cylinder,
CA...control unit.

Claims (1)

A running vehicle body,
A driver's seat that can accommodate a pilot,
a braking device that brakes the traveling vehicle body;
an electric cylinder supported on a floor on which the driver's seat is installed and which operates the braking device;
a control unit that causes the traveling vehicle body to automatically travel along a predetermined travel route, and stores in advance an operating position of the electric cylinder at which the braking device operates, and when the engine speed does not reach a predetermined value during automatic traveling, moves the electric cylinder to the operating position, and brakes the traveling vehicle body with the braking device;
When the electric cylinder moves to the operating position, the electric cylinder is stopped at the operating position for a predetermined time, and after the predetermined time has elapsed, the electric cylinder is moved to a release position where the braking device is not operated,
the control unit moves the electric cylinder between the operating position and the released position when the work vehicle is powered on, and restricts the start of the automatic traveling if the electric cylinder does not reach at least one of the operating position and the released position;
A work vehicle comprising: